Toroidal gasket rings, also known as “O” rings, are typically made of rubber and are commonly used as static seals in the presence of forces which are predominantly perpendicular at a diametric plane. Toroidal gasket rings are also commonly used as dynamic seals in the presence of forces which develop in particular in the diametric plane of the gasket itself.
Likewise, the use of ring-shaped gasket assemblies with quadrilateral sections of Polytetrafluoroethylene or PTFE (known under the trademark TEFLON) is also well-known. This type of gasket assembly presents mechanical and physical characteristics capable of reducing wear and tear; however, this type of gasket assembly does not provide the precise sealing performance of rubber gaskets.
Also well-known in the art is the use of ring-shaped gasket assemblies formed by the simple insertion of rubber toroidal gaskets into ring-shaped supports formed from PTFE. However, the performance of such gasket assemblies has proven to be less than optimal because of the ever present risk of separation of the rubber toroidal gasket from the ring shaped PTFE support. In addition, a loss of the seal between the gasket assembly and the rotating ball within the body of a ball valve can result because of the friction developed by the rotation of the ball on the ring-shaped gasket assembly within the body of the ball valve.
Accordingly, a need remains in the art for a gasket assembly for use in a ball valve which eliminates the above-mentioned inconveniences and makes it possible, to improve valve performance both in terms of ease of use and an increase in service life at the same time.